Soda-lime glass, also called soda-lime-silica glass, is conventionally prepared by melting a mixture of glass-forming materials known as a “glass batch” in a furnace or tank until a substantially homogenous glass melt is produced. It is generally desirable to maintain intimate contact between the glass batch materials during the melting process in order to reduce the melting temperature and “residence time” of the glass melt, i.e., the time required to completely melt all crystalline materials of batch origin. Attempts at reducing glass melt residence times have included reducing the particle size of the materials used to prepare the glass batch. However, finely ground glass batches tend to create more dust and can result in segregation or separation of the glass batch materials due to differences in particle size or density.
A general object of the present disclosure is to provide a soda-lime glass batch in granule form, which can be used to improve the energy efficiency of a glass melting process by reducing the melting temperature and the residence time of the glass melt.
The present disclosure embodies a number of aspects that can be implemented separately from or in combination with each other.
A core-shell granule for producing soda-lime glass, in accordance with one aspect of the disclosure, includes: a plurality of glass batch materials in amounts according to a soda-lime glass batch composition; a core comprising a first portion of the plurality of glass batch materials; and a shell surrounding the core comprising a second portion of the plurality of glass batch materials.
A process for producing a soda-lime glass batch in granule form, in accordance with another aspect of the disclosure, includes: (a) providing a plurality of glass batch materials in amounts according to a soda-lime glass batch composition, (b) mixing a first portion of the plurality of glass batch materials with a first bonding agent to form core granules, and (c) mixing a remaining portion of the plurality of glass batch materials with the core granules and a second bonding agent to form core-shell granules. The plurality of glass batch materials includes a silicon (Si)-containing material, a calcium (Ca)-containing material, and a sodium (Na)-containing material, and the first portion includes a major portion of the silicon (Si)- and calcium (Ca)-containing materials provided with the plurality of glass batch materials, but only a minor portion of the sodium (Na)-containing material provided with the plurality of glass batch materials.
A process for producing soda-lime glass, in accordance with yet another aspect of the disclosure, includes: feeding soda-lime glass batch materials to a glass furnace, wherein said glass batch materials are in the form of layered granules comprising a core that includes silica and limestone, and at least one layer surrounding said core that includes silica and soda ash.